Time to Treatment Failure as a Recorded Treatment-Process Measure in C-CAT. Reply to Comment on "Facility-Level Medical Oncology Specialist Availability and First-Line Time to Treatment Failure in Lung Cancer: A Nationwide C-CAT Registry Analysis. Curr. Oncol. 2026, 33, 462"

We thank Karabuga and Kaya for their Comment on our nationwide C-CAT registry analysis of facility-level medical oncology specialist availability and first-line time to treatment failure (TTF) in lung cancer. We agree that the heterogeneous composition of TTF events and the predominantly post-first-line timing of C-CAT registration are important to interpretation. In this Reply, we clarify that TTF should be interpreted as the duration of a recorded first-line treatment process rather than as a direct measure of progression, treatment efficacy, survival benefit, facility quality, or individual specialist contribution. We also provide group-specific information on endpoint composition and the interval from first-line treatment initiation to C-CAT registration. Because treatment-ending causes were not clinically standardized and registration timing was itself post-treatment and selection-related, we did not perform additional cause-specific or registration-interval-stratified analyses. No new patient-level analysis was performed for this Reply.